The present invention relates to a machine for filling capsules with a powdered pharmaceutical product.
More specifically, the present invention relates to a machine for filling capsulesxe2x80x94each comprising a bottom shell and a top shell fitted to the bottom shellxe2x80x94with a powdered pharmaceutical product, to which the following description refers purely by way of example.
In the pharmaceutical industry, a capsule filling machine is employed comprising a conveyor which moves continuously along a given path and has a number of pockets equally spaced along the path, and each for receiving a respective bottom shell.
The machine also comprises a metering wheel mounted to rotate continuously about a central axis of symmetry, and having a number of metering devices, which are equally spaced about said axis with the same spacing as the pockets, move with the metering wheel along a portion of said path, each in time with a relative pocket, and move with respect to the metering wheel in a direction parallel to the metering wheel axis.
The machine also comprises an annular container housing the powdered pharmaceutical product, and which is mounted to rotate continuously about a further central axis of symmetry parallel to and eccentric with respect to the metering wheel axis, so that each metering device is first positioned facing the container to withdraw a given quantity of pharmaceutical product from the container, and is then positioned facing and coaxial with a relative bottom shell, into which it feeds the withdrawn pharmaceutical product.
Known machines of the type described above have several drawbacks, foremost of which is their relatively low output.
That is, the spacing of the pockets along the path of the conveyor depends on the size of the metering devices measured parallel to the path, and must be at least equal to a minimum value enabling the metering devices to be spaced about the metering wheel.
Moreover, since the angular speed and diameter of the annular container depend on the angular speed and diameter respectively of the metering wheel, there is a limit to the extent to which the output of such machines can be increased by increasing the diameter and/or angular speed of the metering wheel.
That is, the angular speed and diameter of the metering wheel must be kept below respective maximum values to prevent the centrifugal force acting on the pharmaceutical product in the annular container from separating the product into its component parts and/or resulting in nonhomogenous distribution of the product inside the annular container.
It is an object of the present invention to provide a machine for filling capsules with a powdered pharmaceutical product, designed to eliminate the aforementioned drawbacks.
According to the present invention, there is provided a machine for filling capsules with a powdered product, each capsule comprising a bottom shell and a top shell; the machine comprising a conveyor moving continuously along a given path and having a number of pockets equally spaced along said path with a first spacing, and each for receiving a respective bottom shell; and being characterized by also comprising a number of metering wheels rotating continuously about respective axes substantially parallel to one another; each said metering wheel having a number of metering devices equally spaced about the relative said axis with a second spacing, and movable with the relative metering wheel along a relative portion of said path, each in time with a relative said pocket, to feed said product into a relative said bottom shell; said second spacing being equal to the product of said number of metering wheels and said first spacing.